1. Field of the Invention
The invention relates to fermentation byproduct treatment processes and systems and, more particularly, relates to an apparatus and system for separating a fermentation process byproduct into the byproduct's constituent components and for recovering those components.
2. Discussion of the Related Art
Fermentation processes are used in a wide range of industries to produce a variety of products. In the typical fermentation process, a starter or feed product is transformed into other substances in the presence of heat and/or a biological agent to produce a desired product as well as a byproduct. Feed or starter products for typical fermentation processes include fibrous organic materials such as grain meal or protein meal. The desired product of the fermentation process may, for instance, comprise an antibiotic. The byproduct of the fermentation process usually comprises a significant portion of the process' products.
The typical fermentation process byproduct is mixed in a liquid (usually water) and includes 1) insoluble solids, 2) dissolved soluble solids (primarily unconverted sugars), and 3) organic oils and fats. The insoluble solids usually comprise fibers and hence will usually be referred to herein as "fibers" for the sake of convenience. The oils and fats usually include one or more oils and one or more fats and will usually be referred to as "oil" herein for the sake of convenience. The oil usually binds to the fibers during the fermentation process so that it cannot be readily removed from the fibers by mechanical separation. This binding causes several problems, some of which will now be detailed.
The first problem arising from the binding of oil to the fibers of fermentation byproducts is that fiber drying is hindered. Fibers from fermentation process byproducts have a variety of potential applications including as fertilizer and as animal feed supplements. Fiber drying is desirable if not essential for shipment, storage, and/or post-processing of fibers used in most of these applications. However, drying of oil-saturated fibers by conventional methods is very difficult. If drying occurs at temperatures that are high-enough to separate the oil from the fibers by oxidation, the oil is destroyed, and the fiber may be damaged, thereby decreasing the digestibility of proteins in the recovered fibers and rendering the recovered fibers unsuited or at least poorly-suited for use as animal feed supplements or other, related applications. If, however, drying occurs at lower temperatures such that the oil separates from the fibers without oxidation, the oil coagulates on dryer components, reducing drying efficiency and creating fire risks. Some previous attempts to dry oil-bound fibers attempted to alleviate at least some of the problems associated with fiber drying by recycling a substantial percentage of dried products to the dryer inlet so that the resulting blended product that was subject to drying had a lower average oil content than an unblended product. These processes proved inefficient at best, and in most instances, proved infeasible.
A second problem associated with drying oil-bound fibers is that, even if the fibers can be adequately dried, the oil content of the resultant protein meal is too high for many uses. For instance, the fibers of the typical fermentation process byproduct are potentially highly useful as an animal feed supplement. However, because it was heretofore impossible to efficiently remove oils from the fibers during the drying processes, the dried product exhibited a substandard protein/oil ratio for use as a stand-alone feed supplement. That is, for most feed applications, if this product were fed to an animal in sufficient quantities to supply the animal with enough protein to thrive, the animal would consume too much oil with digestive problems. Hence, it was heretofore necessary to blend dried fermentation byproducts with other protein-based feeds to produce a blended feed with an acceptably high protein/oil ratio.
Another problem historically associated with handling fermentation process byproducts (as well as other products containing malodorous substances and/or bacterial contaminants) is that they are, at best, inefficient at sterilizing the byproducts or at destroying or at least rendering inert malodorous substances. Therefore, health and order concerns have placed additional constraints on companies' ability to handle fermentation byproducts and other, similar products.
As a result of the above-mentioned and other problems associated with separating oils from fibers of fermentation byproducts and with drying the oil-laden byproducts, the potential to put these byproducts into commercial use has never been fully realized. In fact, most manufacturers consider fermentation byproducts useful only as landfill materials and therefore must pay for the disposal of the byproducts, often at a cost of up to several million dollars per year and also must deal with potential health problems. Hence, many manufacturers of byproducts that have high concentrations of commercially valuable proteins, sugars, and oils must pay to dispose of these byproducts. The need therefore has arisen to provide a commercially-practical process and system that enable the recovery of valuable components and their associated revenue streams from a fermentation byproduct rather than having to deal with the disposal problems usually associated with the fermentation byproduct.